Cassini's Langmuir probe

Sweden's Institute for Space Physics, IRF, in Uppsala contributed to Cassini's Langmuir probe, described as a weather station for space weather. The Langmuir probe is positively charged therefore attracts the negatively charged electrons in the electrically charged gas, or plasma as it is knowm, prevailing in the surrounding space space. By measuring the current that the charged particles give rise to, the researchers calculate the electron density in space. Using intricate methods, they can also measure the individual speed of the electrons - their temperature, and sometimes also the flow rate of the plasma.